Air-drop folding portable shelter

ABSTRACT

A folding portable shelter which when dropped from an aircraft automatically opens into its erected configuration, locks itself into the erected configuration, and then functions as a parachute to deliver a payload to the ground. The shelter has a ventilating opening in its top, a doorway with a canopy extending from it, and internal partitions. Also, a plurality of the shelters can be joined at their doorways and their bases to form a modular complex shelter.

Burch ..13s/2 O United States Patent 1191 1111 3,724,473

Moss 1 1 Apr. 3, 1973 s41 AIR-DROP FOLDING PORTABLE 1,339,828 5/1920 Lewis et al. ..244/142 SHELTER 2,771,037 11/1956 Simonson ..13s/4 R 3,228,636 1/1966 Lemoigne ..244/145 [76] Inventor: Charles W. Moss, 1169 Aberdeen, 7 Ann Arbor, Mich 43104 Primary Examiner-Peter M. Caun [22] Filed: Oct 5, 1971 Attorney-Olsen and Stephenson [21] Appl. No.: 186,684 [57] ABSTRACT A folding portable shelter which when dropped from [52] U.S. Cl. ..135/4 R, 244/142 an aircraft automatically opens into its erected con- [51] Int. Cl. ..A45f1/00, A45f1/16 figurat n, locks itself int the created configuration, [58] Field of Search 135/1 R, 2, 4 R, 5 E 3; and then functions as a parachute to deliver a payload 244/ 142, 145 to the ground. The shelter has a ventilating opening in its top, a doorway with a canopy extending from it, [56] References Cited and internal partitions. Also, a plurality of the shelters can be joined at their doorways and their bases to UNITED STATES PATENTS form a modular complex shelter. 998,462 7/1911 16 Claims, 14 Drawing Figures PATENTEDAFR 3 1913 Q INVENTOR C/I/ARZES MK Moss B dlm g ATTOR NEYS PATENTEUAPR 3 H75 SHEET 2 OF 3 INVENTOR (/IARLES m Moss BY flfim 5j ATTORNEYS AIR-DROP FOLDING PORTABLE SHELTER BACKGROUND OF THE INVENTION The present invention relates to a portable shelter, which when dropped from an aircraft, automatically opens and locks into its erected configuration, and then functions as a parachute to deliver a payload to the ground. The present invention also relates to the means for achieving the automatic opening and self-locking features of the shelter.

In a disaster situation such as an earthquake or flood, the immediate needs of the population must often be supplied by aircraft since roads and railroads may have been destroyed. Shelter, food, and medicine are usually most urgently needed. Portable shelters such as tents provide the most suitable shelters in such a situation,

' but in order to air-drop tents in the pass they had to be ready for immediate use. Thus every ounce of materialdropped as payload including the airdrop shelterparachute itself.

SUMMARY OF THE INVENTION The present invention includes a self-erecting, selflocking, air-drop shelter, which has an outer flexible cover, with shroud lines attached similarly to a parachute and which has a flexible frame attached to the outer flexible cover to support the flexible cover in its open configuration. The frame has a conical pinnacle positioned atop the shelter which locks open in response to air pressure differential existing during the airdrop and thereby. holds the flexible frame in-a distendedposition to support the outer flexible cover in its erected configuration. The present invention also relates to an air-drop shelter having internal partitions, rooftop ventilation, and canopy covered doorways suitable for interconnecting several shelters together to form a modular complex of shelters.

Thus it is among the objects of the present invention to provide a portable shelter capable of air-dropping and having self-opening and self-locking features. Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS.

FIG. S-is a schematic illustration of the ventilation system of the shelter for winter use;

FIG. 6 is an enlarged side elevational view of a portion of the. shelters frame including the pinnacle top and self-locking mechanism;

FIG. 7 is a top plan view of the hub comprising part of the shelters frame;

FIG. 8 is' an enlarged fragmentary side elevational view of the self-locking mechanism employed by the shelters frame;

FIG. 9 is a side elevational view of the shelter with doorways attached;

FIG. 10 is. an enlarged pictorial view of the shelters doorway, with portions broken away to show internal details;

FIG. 11 is a top sectional view taken on the line 11-11 of FIG. 9, showing the shelter with doorways attached;

FIG. 12 is a top schematic view of three shelters joined to form a modular complex;

FIG. 13 is a side elevational view of the shelter folded and inserted in a container, shown in broken lines, for.

storage or transport; and

FIG. 14 is a sequential pictorial illustration of the shelter being deployed as a parachute.

DESCRIPTION or THE PREFERRED EMBODIMENT Before explaining the present invention indetail, it is. to be understood that the invention is not limited in: its

application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out'in various'ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. I

Referring now to the drawings, a portable shelter 10, capable of being used as a parachute to air-drop a payload for an emergency airlift, for example, has flexible cover 12 such as canvas distensibly supported by. a folding flexible frame 14 shown in FIG. 3. The frame comprises a plurality of flexible ribs 16 made of any suitable flexible material such as fiberglass or metal. The ribs 16 are inserted into tunnels 18 formed in the flexible cover 12, as shown in FIGS. I and 2 and as shown enlarged in FIG. 10, and are connected to the flexible cover 12 at their lower ends by any suitable means to insure that the flexible cover 12 does not ride up the ribs 16 when the shelter is in its erected configuration. The ribs 16 are pivotally interconnected to each other at their top ends by means of a hub 20 with enr gaging pins 22 as shown in FIGS. 7 and 8. 1 With reference to FIGS. 1 and 6, a conical shape pinnacle 24 comprising part of the frame 14 and having an outer conical cover 26 of flexible material similar to v the flexible cover 12 and a shaft 28 extending downward along the axis of the conical pinnacle 24, is

mounted atop the shelter and serves to hold the flexible I ribs 16 in a flexed arcuate shaped when the shelter is erected. As shown by the solid lines in FIG. 6, this flexing function is accomplished when the hub 20 which is slidably mounted on shaft 28 is secured in its lowest position on the shaft 28 by a spring clamp 30 which engages a shoulder 32 of the hub 20. FIG 8 provides an enlarged view of the hub 20 engaged by the spring clamp 30. Referring again to FIG. 6, the ribs 16 are thus flexed by the action of the conical cover 26, attached to the ribs 16 via the tunnel 18 at points 33 which creates an upward tension on the ribs 16 while the shaft 28 with the hub 20 in its lowest position, forces the hub 20 downward to create a bowing action in the ribs 16 which are constrained by the shape of the cover 12.

The broken lines in FIG. 6 show the pinnacles configuration when the shelter is folded for storage. The hub after being manually disengaged spring clamp 30, can freely slide upward along shaft 28 thus allowing the pinnacle 24 to collapse the ribs 16' to fold inwardly as a result.

When the shelter 10 is airdropped, shown sequentially in FIG. 14, shroud lines 34 are suitably attached to the flexible cover 12 at points 36. In FIG. 10, one of the points 36 is shown enlarged. The point 36 is defined by the intersection of the lower end of rib 16 and the flexible cover 12. A tab 38 is provided on the flexible cover 12 at each of the points 36 for attachment of the shroud lines 34 and for staking the shelter 10 down when it is erected and sitting on the ground. A payload 40 is connected to the shroud lines 34 at their common point. When the shelter 10 and attached payload 40 are dropped from an aircraft, the shelter 10 functions as a parachute as shown sequentially in FIG. 14 to deliver the payload 40 to the ground. Once on the ground the shelter 10 remains locked in its distended erected configuration as seen in the last step of FIG. 14. The distending of the shelter 10 during an airdrop is caused by two coacting phenomenon. First, air rushing under the flexible cover 12 causes it to balloon slightly as indicated in FIG. 14, step 2. Secondly, and with reference to FIGS. 3'and 6 again, air also rushes through a hole 42 in the flexible cover 12 situated beneath the pinnacle 24. The hole 42 is formed because the flexible cover 12 with its tunnels 18 does not extend to enclose the hub 20. The air thus introduced into the pinnacle 24 through hole 42 causes the pinnacle 24' to balloon into the shape of pinnacle 24. As the pinnacle 24' balloons in response to the air pressure the hub 20 slides downward on shaft 28 and is locked in place by spring clamp 30. Once the hub 20 is locked the ribs 16 are bowed and the shelter 10 is fully distended to conform to the shape of flexible cover 12 as shown in step 3 of FIG. 14. When the shelter 10 reaches the ground,the frame 14 stays locked open by means of spring clamp 30, and the shelter remains distended and erect as the last step illustrated in FIG. 14.

When not in use the shelter 10 can be folded as shown in FIG. 13 and inserted in a cylindrical container 42, shown in broken outline, for storage and transport.

Once the shelter 10 has been airdropped and on the ground, its construction provides several advantages. The hole 42 between the flexible cover 12 and the pinnacle 24, which allows air to pass into the pinnacle 24 during descent, serves as a rooftop ventilator. Referring to FIG. 4, airflow through the shelter 10 is diagrammed for summer use with an external heat source 44. In addition to hole 42, there is a gap 46 between the conical cover 26 of the pinnacle 24 and the flexible cover 12. The gap 46 results because the conical cover 26 is only attached to the flexible cover 12 at discreet points 33 corresponding to the intersection of the conical cover 26 and the tunnels 18 of the flexible cover 12, and seen in FIGS. 1 and 2. Due to the external heat source 44 the outside of the flexible cover 12 is heated initially and the hot air rises along it as shown. The air next to the cover 12'inside the tent heats and also rises along the concave wall 48 thus setting up acounterclockwise rotary flow of air. The rotary flow pulls cool air present within a low pressure cone 50 formed above the tent into the shelter 10 through gap 46, and simultaneously air escapes at the bottom to provide the desired ventilation.

With reference to FIG. 5, circulation of air for winter use with internal heat source 52 is diagrammed. The air inside the shelter 10 is heated by the heat source 52 and rises toward the pinnacle 24. At the same time, cool air along the flexible cover 12 sinks to replace the warm air and clockwise circulation as shown begins. Because of the circulation,the warm air tends to proceed toward the flexible cover 12 where it is cooled and recirculated. As some heated air escapes at the gap 46, more cool air flows into the shelter 10 at the bottom to insure continuous ventilation.

Referring to FIGS. 9-11, the shelter 10 also may be equipped with a doorway 54 comprising a closable vertical slit or opening 56 in a section of the flexible cover 12 and a canopy 58. The canopy is made of flexible material similar to the flexible cover 12 and is attached to the shelter 10 along two lines 60 each defined by the tunnels 18 within the flexible cover 12. Attachment of the canopy 58 to the flexible cover 12 can be permanent by stitching directly along the tunnel 18, for example, or temporarily for removal during airdrop by means of a zipper along the tunnel 18. Supporting rods 62 are inserted into channels 64 of the canopy 58 and are supported by the flexible ribs 16 at point 36 by suitable supporting attachment means. The rods 62 extend upward and outward to form a peak 66. The peak 66 thus formed extends beyond the base of the shelter 10 as seen in FIG. 11 and protects the slit 56 from rain or snow. I

Internal partition 68 and 70 in FIG. 3 comprise another advantageous feature of the shelter 10 and can be either temporarily or permanently attached to the flexible cover 12 along any internal line 71 defined by therib 16 contacting the flexible cover 12. The partitions can be arranged or other similar partitions added to adapt the shelter most advantageously to its intended use.

With reference to FIG. 12, three shelters 70, 72 and 74, each similar to shelter 10 have doorways 76 and 78, 80 and 82, 84 and 86, respectively are interconnected to form a modular complex structure 87. The three shelters 70, 72 and 74 are joined along common sides of their bases at lines 88 and 90, and the doorways 78, 82 and 84 are joined at a common point 92. The'three shelters 70, 72 and 74 thus form modular complex 87 which could be used for issuing clothing to refugees, for example, with a line of people forming at doorway 76, moving past station 96, through doorways 78 and 84, around stations 98 and 100, and out doorway 86.

Shelter 72 could be used for storage. Other complexes 1 could be configured to provide field hospitals, mess halls, command posts, and so forth using different numbers of shelters and internal partitions.

It is claimed:

1. A fold portable shelter adapted to be erected as an incident to an airdrop from an aircraft, comprising a flexible cover conforming generally to the shape of a parachute, shroud lines operatively connected at one of their ends to the lower peripheral edge of the cover and commonly connected at their other ends so as to form with the cover a parachute-like structure, a flexible frame operatively attached to said cover and responsive to distending of said cover into the shape of a parachute to flex into an open shape conforming to the shape of the distended cover, said frame including selflocking means to lock the frame in said open shape whenflexed open so that when airdropped the shelter can land in an erected state.

2. A folding portable shelter as defined in claim I, wherein saidflexibleframe includes a central hub, a plurality of flexible ribs having their top end portions pivotally mounted on said hub and adapted to flex into archate shape, said flexible cover being disposed in flexing-restraining and flexing-producing engagement with said ribs and having a hole concentric with said hub.

3. A folding portable shelter as defined in claim 2, wherein saidself-locking means is a structural, essentially conical shaped pinnacle positioned above said hub and having a base area capable of covering said holdand structurally interconnecting said hub and said flexible ribs so that said flexible ribs are held in distensible engagement with said flexible coverby said conical pinnacle.

4. A folding portable shelter as defined in claim 3, wherein said conical pinnacle comprises an outer conical' cover of flexible material secured at a ,line defined by the base. of said conical pinnacle to said flexible rib at a point below said top end portion of said flexible ribs, and a shaft member positioned along a line defined by the axis of said conical pinnacle engaging said outer conical cover at its upper end to form an apex and having spring clamp means at its lower end with saidhub slidably mounted therebetween, said hub being capable of engagement by said spring clamp means when said flexible ribs are distended and arcuately shaped in response .to higher air pressure on the inside of said shelter and when said conical cover is under tension from higher air pressure within caused when said shelter is being utilized as a parachute, and said hub capable of freely sliding upward on said shaft when said spring clamp means is disengaged and said frame is folded.

5. A folding portable shelter as defined in claim 4, wherein said flexible cover has internal partitions comprising essentially sector shaped pieces of flexible material secured along a line defined by said arcuate shapedyribs and extending between the plane defined by the base of said flexible cover and a point near the top of said flexible cover when said flexible cover is in distended engagement with said flexible rib.

6. A folding portable shelter as defined in claim 4, wherein said flexible cover has a doorway means comprising a vertical, arcuately extending opening in said flexible cover and a canopy of flexible material attached externally along a line defined by adjacent ribs, and having supporting rods, each said supporting rod being attached to one end to the lower end of said adjacentflexible ribsthen extending outward from said flexible cover and upward to form a peak with said flex- 7. A folding portable shelter comprising a distensible flexible cover, a supporting frame for said flexible cover including a central hub, a plurality of flexible ribs having their top end portions pivotally mounted on said hub and adapted to flex into arcuate shape, said flexible cover being disposed in flexingqestraining engagement with said ribs, and a structural, essentially conical shaped pinnacle positioned above said hub and structurally interconnecting said hub and said flexible ribs so that said flexible ribs are held in distensible engagement with said flexible cover by said conical pinnacle.

8. A folding portable shelter as defined in claim 7, wherein said conical pinnacle comprises an outer conical cover of flexible material secured at a line defined by the base of said conical pinnacle to said flexible ribs at a point below said top end portion of said flexible ribs, and a. shaft member positioned along a line defined by the axis of said conical pinnacle engaging said outer conical coverat the upper end of said shaft member to form the apex of said conical pinnacle and having spring clamp means at its lower end with said hub slidably mounted on said shaft member therebetween, said hub capable of being engaged by said spring clamp means when said flexible ribs are in their distended engagement with said flexible covet and said hub capable of freely sliding upward when said spring clamp means is disengaged'and said frame is folded.

9. A folding portable shelter as defined in claim 8, wherein said flexible cover is provided with a hole smaller than a circle defined by the base line of said conical pinnacle so that ventilating .air may pass through said hole and then between said conicalpinnacle and said flexible cover along a line defined by the base of said conical pinnacle. r

10. A folding portable shelter as defined in claim 8 wherein said flexible cover has internal partitions comprising, essentially sector shaped pieces of flexible material secured along a line defined by said arcuate shaped ribs and extending between the plane defined by the base of said flexible cover and a point near the top of said flexible cover when said flexible cover is in distended engagement with said flexible ribs.

l1. A folding portable shelter as defined in claim 8 V of folding individual shelters interconnected, each having a distensible flexible cover, a supporting frame for said flexible cover including a central hub, a plurality of 'flexible ribs having their top end portions pivotally mounted on said hub and adapted to flex into arcuateshape, said flexible cover being disposed in flexingrestraining engagement with said ribs, and astructural,

said hub and structurally interconnecting said hub and said flexible ribs so that said flexible ribs are held in distensible engagement with said flexible cover by said conical pinnacle wherein said flexible cover has door way means comprising a vertical arcuately extending opening and a canopy of flexible material attached externally along a line defined by adjacent flexible ribs, and having supporting rods, each said supporting rods being attached at one end to the lower end of said adjacent flexible ribs then extending outward and away from said flexible cover and upward to form a peak with said flexible material attached along the extension of said supporting rods so that said canopy extends above and outward from said opening.

13. A portable modular shelter of claim 12 wherein said individual shelter are connected together at the peak of said doorway.

14. A portable modular shelter of claim 13 wherein said individual shelters having said conical pinnacle comprising an outer conical cover of flexible material secured at a line defining the base of said conical pinnacle to said flexible ribs at a point below said top end portion of said flexible ribs, and a shaft memberpositioned along a line defining the axis of said conical pinnacle engaging said outer conical cover at the upper end of said shaft member to form the apex of said conical pinnacle and having spring clamp means at its lower end with said hub slidably mounted on said shaft member therebetween, said hub capable of being engaged by said spring clamp means when said flexible ribs are in their distended engagement with said flexible cover and said hub capable of freely sliding upward when said spring clamp means is disengaged and said frame is folded.

15. A portable modular shelter of claim 14 wherein each individual shelter has said flexible cover which has a hole therein smaller than a circle defined by the base line of said conical pinnacle so that ventilating air may pass through said hole and then between conical pinnacle and said flexible cover along said line defined by the base of said conical pinnacle.

16. A portable modular shelter of claim 14, wherein each individual shelter has said flexible cover which has internal partitions comprising essentially sector shaped pieces of flexible material secured along a line defined by said arcuate shaped ribs and extending between the plane defined by the base of said flexible cover and a point near the top of said flexible cover when said flexible cover is in distended engagement with said flexible ribs. 

1. A fold portable shelter adapted to be erected as an incident to an airdrop from an aircraft, comprising a flexible cover conforming generally to the shape of a parachute, shroud lines operatively connected at one of their ends to the lower peripheral edge of the cover and commonly connected at their other ends so as to form with the cover a parachute-like structure, a flexible frame operatively attached to said cover and responsive to distending of said cover into the shape of a parachute to flex into an open shape conforming to the shape of the distended cover, said frame including self-locking means to lock the frame in said open shape when flexed open so that when airdropped the shelter can land in an erected state.
 2. A folding portable shelter as defined in claim 1, wherein said flexible frame includes a central hub, a plurality of flexible ribs having their top end portions pivotally mounted on said hub and adapted to flex into archate shape, said flexible cover being disposed in flexing-restraining and flexing-producing engagement with said ribs and having a hole concentric with said hub.
 3. A folding portable shelter as defined in claim 2, wherein said self-locking means is a structural, essentially conical shaped pinnacle positioned above said hub and having a base area capable of covering said hold and structurally interconnecting said hub and said flexible ribs so that said flexible ribs are held in distensible engagement with said flexible cover by said conical pinnacle.
 4. A folding portable shelter as defined in claim 3, wherein said conical pinnacle comprises an outer conical cover of flexible material secured at a line defined by the base of said conical pinnacle to said flexible rib at a point below said top end portion of said flexible ribs, and a shaft member positioned along a line defined by the axis of said conical pinnacle engaging sAid outer conical cover at its upper end to form an apex and having spring clamp means at its lower end with said hub slidably mounted therebetween, said hub being capable of engagement by said spring clamp means when said flexible ribs are distended and arcuately shaped in response to higher air pressure on the inside of said shelter and when said conical cover is under tension from higher air pressure within caused when said shelter is being utilized as a parachute, and said hub capable of freely sliding upward on said shaft when said spring clamp means is disengaged and said frame is folded.
 5. A folding portable shelter as defined in claim 4, wherein said flexible cover has internal partitions comprising essentially sector shaped pieces of flexible material secured along a line defined by said arcuate shaped ribs and extending between the plane defined by the base of said flexible cover and a point near the top of said flexible cover when said flexible cover is in distended engagement with said flexible rib.
 6. A folding portable shelter as defined in claim 4, wherein said flexible cover has a doorway means comprising a vertical, arcuately extending opening in said flexible cover and a canopy of flexible material attached externally along a line defined by adjacent ribs, and having supporting rods, each said supporting rod being attached to one end to the lower end of said adjacent flexible ribs then extending outward from said flexible cover and upward to form a peak with said flexible material of said canopy attached along the extension of said supporting rods.
 7. A folding portable shelter comprising a distensible flexible cover, a supporting frame for said flexible cover including a central hub, a plurality of flexible ribs having their top end portions pivotally mounted on said hub and adapted to flex into arcuate shape, said flexible cover being disposed in flexing-restraining engagement with said ribs, and a structural, essentially conical shaped pinnacle positioned above said hub and structurally interconnecting said hub and said flexible ribs so that said flexible ribs are held in distensible engagement with said flexible cover by said conical pinnacle.
 8. A folding portable shelter as defined in claim 7, wherein said conical pinnacle comprises an outer conical cover of flexible material secured at a line defined by the base of said conical pinnacle to said flexible ribs at a point below said top end portion of said flexible ribs, and a shaft member positioned along a line defined by the axis of said conical pinnacle engaging said outer conical cover at the upper end of said shaft member to form the apex of said conical pinnacle and having spring clamp means at its lower end with said hub slidably mounted on said shaft member therebetween, said hub capable of being engaged by said spring clamp means when said flexible ribs are in their distended engagement with said flexible cover and said hub capable of freely sliding upward when said spring clamp means is disengaged and said frame is folded.
 9. A folding portable shelter as defined in claim 8, wherein said flexible cover is provided with a hole smaller than a circle defined by the base line of said conical pinnacle so that ventilating air may pass through said hole and then between said conical pinnacle and said flexible cover along a line defined by the base of said conical pinnacle.
 10. A folding portable shelter as defined in claim 8 wherein said flexible cover has internal partitions comprising essentially sector shaped pieces of flexible material secured along a line defined by said arcuate shaped ribs and extending between the plane defined by the base of said flexible cover and a point near the top of said flexible cover when said flexible cover is in distended engagement with said flexible ribs.
 11. A folding portable shelter as defined in claim 8 wherein said flexible cover has doorway means comprising a vertical, arcuately extending opening in said hemispheric cover and a canopy of flexIble material attached externally along a line defined by adjacent flexible ribs, and having supporting rods, each said supporting rod being attached to one end to the lower end of said adjacent flexible ribs then extending outward from said flexible cover and upward to form a peak with said flexible material attached along the extension of said supporting rods.
 12. A portable modular shelter comprising a plurality of folding individual shelters interconnected, each having a distensible flexible cover, a supporting frame for said flexible cover including a central hub, a plurality of flexible ribs having their top end portions pivotally mounted on said hub and adapted to flex into arcuate shape, said flexible cover being disposed in flexing-restraining engagement with said ribs, and a structural, essentially conical shaped pinnacle positioned above said hub and structurally interconnecting said hub and said flexible ribs so that said flexible ribs are held in distensible engagement with said flexible cover by said conical pinnacle wherein said flexible cover has door way means comprising a vertical arcuately extending opening and a canopy of flexible material attached externally along a line defined by adjacent flexible ribs, and having supporting rods, each said supporting rods being attached at one end to the lower end of said adjacent flexible ribs then extending outward and away from said flexible cover and upward to form a peak with said flexible material attached along the extension of said supporting rods so that said canopy extends above and outward from said opening.
 13. A portable modular shelter of claim 12 wherein said individual shelter are connected together at the peak of said doorway.
 14. A portable modular shelter of claim 13 wherein said individual shelters having said conical pinnacle comprising an outer conical cover of flexible material secured at a line defining the base of said conical pinnacle to said flexible ribs at a point below said top end portion of said flexible ribs, and a shaft member positioned along a line defining the axis of said conical pinnacle engaging said outer conical cover at the upper end of said shaft member to form the apex of said conical pinnacle and having spring clamp means at its lower end with said hub slidably mounted on said shaft member therebetween, said hub capable of being engaged by said spring clamp means when said flexible ribs are in their distended engagement with said flexible cover and said hub capable of freely sliding upward when said spring clamp means is disengaged and said frame is folded.
 15. A portable modular shelter of claim 14 wherein each individual shelter has said flexible cover which has a hole therein smaller than a circle defined by the base line of said conical pinnacle so that ventilating air may pass through said hole and then between conical pinnacle and said flexible cover along said line defined by the base of said conical pinnacle.
 16. A portable modular shelter of claim 14, wherein each individual shelter has said flexible cover which has internal partitions comprising essentially sector shaped pieces of flexible material secured along a line defined by said arcuate shaped ribs and extending between the plane defined by the base of said flexible cover and a point near the top of said flexible cover when said flexible cover is in distended engagement with said flexible ribs. 